1. Field of the Invention
The present invention relates to heat pumps, devices that move heat from a heat source to a warmer heat sink. More specifically, it relates to Bernoulli heat pumps.
2. Discussion of Related Art
Heat engines are devices that move heat from a heat source to a heat sink. Heat engines can be divided into two fundamental classes distinguished by the direction in which heat is moved. Heat spontaneously flows “downhill”, that is, to lower temperatures. As with the flow of water, such “downhill” heat flow can be harnessed to produce mechanical work, as illustrated by internal-combustion engines, e.g. Devices that move heat “uphill”, that is, toward higher temperatures, are called heat pumps. Heat pumps necessarily consume power. Refrigerators and air conditioners are examples of heat pumps. Most commonly used heat pumps employ a working fluid whose temperature is varied over a range that includes the temperatures of both the source and sink between which heat is pumped. This temperature variation is commonly accomplished by compression of the working fluid. Bernoulli heat pumps effect the required temperature variation by converting random molecular motion (temperature and pressure) into directed motion (macroscopic fluid flow). A fluid spontaneously converts random molecular motion into directed motion when the cross sectional area of a flow is reduced to form a Venturi. Temperature and pressure reflect random molecular motion and are reduced when a flow is nozzled, an effect called the Bernoulli principle. Whereas compression consumes power, Bernoulli conversion does not.
The Bernoulli effect is well known, best known perhaps, as the basis for aerodynamic lift. Three earlier U.S. patents (U.S. Pat. Nos. 3,049,891, 3,200,607 and 4,378,681) describe devices designed to exploit Bernoulli conversion for the purpose of pumping heat. All three use stationary, solid-walled nozzles to effect the required variation of the cross-sectional area of a fluid flow.